Looks good, my mast was ok so I just went with the seal.Most instructions to fit say cut the old seal away and fit the new seal over the top
dont bother its a load of agro and never fits well, do yourself a favour and remove the trim off of the inside of the boot its only 5 or so trim clips
and a screw and remove the rear light, its held on by 3 8mm nuts and pull the
connection off the back of the light, you have then got access to the underneath of the antenna ,you will then need a 22mm socket to
remove the captive nut under the wing, the best socket to use is one designed to remove a lambda sensor as it has a slit in it for the wiring to
fit in, undo the nut pull the wiring through the nut and remove through the wing, its just a matter of fitting the seal and replacing being careful
not to cross thread the the nut on the threaded piece of the base, and refit the light, again careful when you remove and reinstall the light, the
nuts are easy to drop and they under up behind the roof pump, possible to get back dependant on the size of your hands otherwise its just the
removal of the pump to retrieve again just 3 nuts, I will take a few pictures of it installed later when it gets light here in the UK.
If you are still worried about water ingress get yourself some 3M weather sealant, and put a drop under the seal befor you fit to the wing.